The cutaneous pathology of lupus erythematosus: a review

Lymphatic messengers: Non-antigen soluble mediators from diseased tissues to draining lymph nodes

Tissues deliver not only antigens and cells via afferent lymphatics to draining lymph nodes during immune responses but also deliver soluble molecules that reflect the state of the tissue. In autoimmune diseases, these signals from affected tissues can potentially impact the magnitude or other characteristics of autoimmune responses generated in lymph nodes. Here, we highlight recent studies illustrating the nature of these soluble signals relevant to lupus skin and in lymphatic fluid draining the gut in inflammatory bowel disease. We also highlight the role of lymph node stromal cells as recipients of lymph borne signals. Identifying the molecules delivered from the tissues and how exactly they modulate immune function in draining lymph nodes will help us to better understand aberrant immunity in disease.

Ultraviolet Radiation-Induced Tolerogenic Dendritic Cells in Skin: Insights and Mechanisms

Ultraviolet (UV) radiation has profound effects on the immune system, including the induction of tolerogenic dendritic cells (DCs), which contribute to immune suppression and tolerance. This review explores the roles of conventional CD11c⁺ DCs, as well as cutaneous Langerhans cells and CD11b⁺ myeloid cells, in UV-induced immune modulation. Two key mechanisms underlying the immunosuppressive relationship between UV and DCs are discussed: the inactivation of DCs and the induction of tolerogenic DCs. DCs serve as a critical link between the innate and adaptive immune systems, serving as professional antigen-presenting cells. In this context, we explore how UV-induced DCs influence the activity of specific T cell subsets, including regulatory T lymphocytes and T helper cells, and shape immune outcomes. Finally, we highlight the implications of UV-induced tolerogenic DCs in select dermatologic pathologies, including cutaneous lupus, polymorphic light eruption, and skin cancer. Understanding the mechanisms by which UV radiation alters DC function offers insights into the complex interplay between environmental factors and immune regulation, providing potential avenues for preventive and therapeutic intervention in UV-induced skin diseases.

Histopathologic Overlap Between Bullous Lupus Erythematosus and Linear IgA Bullous Dermatosis: A Comparative Study

ABSTRACT

Bullous lupus erythematosus (BLE) and linear IgA disease (LAD) are rare autoimmune subepidermal blistering diseases, with overlapping features despite different pathogenetic mechanisms. Diagnosis is based on immunofluorescence and serology. This retrospective study was undertaken to compare the histopathologic features of BLE and LAD (11 cases each). The mean age was 36 years in both groups, and female preponderance was noted in BLE. Clinically, all cases presented as tense, itchy blisters distributed over the trunk, face, and extremities. Subepidermal neutrophil-rich blisters were seen in 60% BLE and 54.54% LAD cases. Eosinophils in the blisters were noted in 4 cases (36.4%) of linear IgA bullous dermatosis, but not in any of the BLE cases. The adjacent epidermal changes noted include spongiosis (33%; 40%), papillary microabscesses (22%; 20%), and basal tagging by neutrophils (77%; 70%). Superficial perivascular inflammation was seen in all cases while deep perivascular inflammation was observed in 54% BLE and 36% LAD cases. Lymphocytes were the predominant infiltrate. Increased dermal mucin was seen in 60% BLE and 45% LAD cases. None of the histopathologic features showed a statistically significant difference between the 2 groups. Hence, histopathology alone is of limited value in distinguishing the 2 groups. Diagnosis rests on immunofluorescence and serologic findings, which should be used even in cases that seem to be classic LAD or patients without history of systemic lupus erythematosus.

IRF8 in Conjunction With CD123 and CD20 to Distinguish Lupus Erythematosus Panniculitis From Subcutaneous Panniculitis-like T-Cell Lymphoma

Distinguishing lupus erythematosus panniculitis (LEP) from subcutaneous panniculitis-like T-cell lymphoma (SPTCL) is a diagnostic challenge with important clinical implications. Immunohistochemical expression of interferon regulatory factor 8 (IRF8) has been shown to highlight cells with plasmacytoid dendritic cell differentiation. Considering that the presence of plasmacytoid dendritic cells highlighted by CD123 immunolabeling is a well-described feature that supports LEP over SPTCL, we hypothesized that IRF8 immunohistochemistry can be used as a diagnostic test to improve accuracy in differentiating LEP from SPTCL. In this study, we assessed the expression of IRF8, CD123, and CD20 in 35 cutaneous biopsies from 31 distinct patients, which included 22 cases of LEP and 13 cases of SPTCL. We found that clusters of IRF8-positive cells within the dermis, and away from subcutaneous fat, could discriminate LEP from SPTCL ( P =0.005). Similarly, CD123-positive clusters in any location were observed in LEP but absent in all cases of SPTCL. In addition, we found that dermal CD20-predominant lymphoid aggregates could help discriminate LEP from SPTCL ( P =0.022). As individual assays, IRF8, CD123, and CD20 were highly specific (100%, 100%, and 92%, respectively) though poorly sensitive (45%, 29%, and 50%, respectively). However, a panel combining IRF8, CD123, and CD20, with at least 1 positive marker was more accurate than any individual marker by receiver operating characteristic curve analysis. Our study provides a rationale for potentially including IRF8 as part of an immunohistochemical panel composed of other currently available markers used to differentiate LEP from SPTCL.

The role of eosinophils in the differential diagnosis of inflammatory skin diseases

Eosinophils are known to be present in inflammatory skin diseases, but their diagnostic utility is not well established. Upon review of the published status of lesional eosinophils, several categories were identified. 1) Lesional eosinophils highly characteristic such that, in their absence, the pathologist may question the diagnosis. These include arthropod bite reactions and scabies, urticarial dermatitis, and other eosinophilic dermatoses. 2) Lesional eosinophils rare or absent, such that, in their presence, the pathologist may question the diagnosis. These include pityriasis lichenoides, graft versus host disease, and connective tissue disorders. 3) Lesional eosinophils variable and, while in some cases expected, are not required for diagnosis. These include drug reactions, atopic dermatitis and allergic contact dermatitis. 4) Lesional eosinophils variable and not expected but may be seen to a limited extent. These include lichen planus and psoriasis.

Updates on the dermatopathology of pregnancy-associated skin conditions

Pathologists provide valuable input in the dermatological care of pregnant patients in various contexts. This article provides dermatopathology updates on cutaneous changes associated with pregnancy, organized based on the following classification system: physiological skin changes in pregnancy, specific dermatoses of pregnancy, dermatoses modified in pregnancy, and skin neoplasms in pregnancy. Awareness of the impact of pregnancy on the skin by pathologists is important, as this is an opportunity to contribute to diagnostic precision in this patient population.

Subacute cutaneous lupus erythematosus: A facultative paraneoplastic dermatosis

Subacute cutaneous lupus erythematosus (SCLE) is a photosensitive dermatosis characterized by a nonscarring papulosquamous eruption and specific antibodies in the patient's serum. Genetic and environmental factors represent the leading causes of SCLE; however, several case reports in the literature link SCLE to various types of cancer. This review assesses the association between SCLE and neoplastic disorders. A PubMed search was performed for all relevant publications on cancer-associated SCLE from 1982 to 2022. This review supports the hypothesis that SCLE should be considered a facultative paraneoplastic phenomenon. It also emphasizes the importance of cancer screening in patients presenting SCLE manifestations.

Leukocytoclastic vasculitis in association with linear epidermal basement membrane zone immunoglobulin deposition: Linear vasculitis

Cutaneous leukocytoclastic vasculitis (LCV) has a distinctive clinical and light microscopic presentation; however, the etiologic basis of LCV is varied. Most cases are attributable to immune complex deposition within a vessel wall and represent an Arthus type III immune complex reaction. The prototypic immunoreactant profile is characterized by granular deposits of components of complement activation in concert with immunoglobulin within the cutaneous vasculature. We encountered nine patients with vasculitic and/or vesiculobullous clinical presentations exhibiting an LCV in association with an immunoreactant profile characterized by homogeneous linear deposits of immunoglobulin along the dermal epidermal junction in a fashion resembling an autoimmune vesiculobullous disease. Among the clinical presentations were palpable purpura, urticarial vasculitis, and vesiculobullous eruptions with supervening purpura. Two patients with Crohn disease presented with classic palpable purpura with biopsy-proven LCV, and direct immunofluorescence (DIF) studies demonstrated linear immunoglobulin G (IgG) with floor localization on the salt-split skin assay. Four patients with systemic lupus erythematosus (SLE) showed purpuric vesiculobullous lesions, with evidence of a neutrophilic interface dermatitis and LCV in three of the four. The remaining patient had urticarial nonbullous lesions showing small-vessel vasculitiswith a neutrophilic interface dermatitis. In all of the patients with SLE, DIF studies showed linear immunoglobulin deposits within the basement membrane zone (BMZ). These constellation of findings clinically, light microscopically, and by immunofluorescence were those of a vasculitic presentation of bullous systemic lupus erythematosus. Two patients had linear IgA disease, which was drug induced in one and paraneoplastic in the other, and the dominant morphology on biopsy in both cases was an LCV. One patient microscopically demonstrated drug-associated and eosinophilic enriched LCV with DIF studies showing striking linear deposits of IgG suggestive of bullous pemphigoid, which was consistent with a vasculitic presentation of drug-induced bullous pemphigoid. In all cases, typical granular vascular immunoglobulin and complement deposition compatible with immune complex mediated vasculitis was observed. It is likely that local immune complexes derived from BMZ antigen bound to antibody are pathogenically relevant. We propose the designation of linear vasculitis for this unique scenario of LCV and linear immunoglobulin epidermal BMZ staining, which in some cases represents a vasculitic presentation of conventional autoimmune vesiculobullous disease.

A rare case of suspected lupus erythematous panniculitis as the presenting skin feature of juvenile dermatomyositis: A case report

Juvenile dermatomyositis is a rare autoimmune myopathy of childhood, associated with systemic vasculopathy, primarily affecting the capillaries. Panniculitis is seen histologically in about 10% of patients with dermatomyositis; however, its clinical presentation is rare, with only 30 cases presented in the literature to date. The histopathology overlaps with other inflammatory disease states, and is almost identical to the panniculitis seen in lupus erythematous panniculitis. In the cases with both panniculitis and dermatomyositis, skin and muscle inflammation is usually the first clinical manifestation. We present a case of a 16-year-old female with panniculitis as the initial presenting feature of juvenile dermatomyositis in the context of a prior diagnosis of indeterminate colitis.

First Presentation of Systemic Lupus Erythematosus in a 24-Year-Old Male following mRNA COVID-19 Vaccine

The SARS-CoV-2 viral pandemic has had an immeasurable global impact, resulting in over 5 million deaths worldwide. Numerous vaccines were developed in an attempt to quell viral dissemination and reduce symptom severity among those infected. Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by the production of antinuclear autoantibodies (ANAs) with heterogenic clinical manifestations, secondary to immune complex deposition in a multitude of organ systems. There are scarcely reported cases of SLE development following COVID-19 mRNA vaccination. We present a case of a 24-year-old male without preexisting conditions or family history of autoimmune disorders, presenting with SLE following the first dose of the SARS-CoV-2 Pfizer-BioNTech mRNA vaccine.

Overexpression of cathepsin S exacerbates lupus pathogenesis through upregulation TLR7 and IFN-α in transgenic mice

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease that affects multiple organs. Recent studies suggest relevance between cysteine protease cathepsin S (CTSS) expression and SLE. To investigate the mechanism of CTSS in SLE, CTSS-overexpressing transgenic (TG) mice were generated, and induced lupus-like symptoms. Eight months later, the TG mice spontaneously developed typical SLE symptoms regardless of the inducement. Furthermore, we observed increased toll-like receptor 7 (TLR7) expression with increased monocyte and neutrophil populations in the TG mice. In conclusion, overexpression of CTSS in mice influences TLR7 expression, autoantibodies and IFN-α, which leads to an autoimmune reaction and exacerbates lupus-like symptoms.

A novel humanized cutaneous lupus erythematosus mouse model mediated by IL-21-induced age-associated B cells

Cutaneous lupus erythematosus (CLE) is a relapsing autoimmune disease, but key elements that drive disease initiation and progression remain elusive. To date, the lack of ideal murine model which resemble human cutaneous lupus makes it extremely challenging for moving mechanistic discoveries and novel therapeutics. Here, we prompt a humanized murine model to develop an inducible rapid-onset murine that performs cutaneous rather than systemic lupus, depending on the successful human immune system reconstruction from active lupus patients and UVB irradiation as for essentially pathogenic triggers. In addition, we demonstrate a newly discovered population of B cell with a unique phenotype, that of the age-associated B cell (ABC, T-bet⁺ CD11b⁺), exhibits B cell clusters in humanized cutaneous lupus. In the response of IL-21 and TLR7/9 signals, recruitment of autoreactive B cells to the position of inflammation with subsequent localized antibody production of IgG2a, IgG2b, IgG3, has the potential to exacerbate ongoing inflammation and thus driving lupus-like autoimmunity in a B-cell-dominant fashion. Overall, our model provides a relevant system for exploring the pathophysiology of cutaneous lupus, a suitable model for drug development, as well as updating a potential role of IL-21 and TLR7/9 to be targeted by biologics.

Recognition and Management of Cutaneous Connective Tissue Diseases

Connective tissue diseases (CTDs) encompass a broad spectrum of clinical presentations that involve multidisciplinary management. Cutaneous findings are common in CTD and careful examination of these features aids in appropriate diagnosis and subsequent evaluation. Thorough work-up of CTD is crucial to properly identify disease subtypes and systemic involvement. Management plans can be developed based on diagnosis and systemic manifestations of disease. Disease management often requires treatment with pharmacotherapies with potential for toxicities, further underscoring the importance of diagnostic accuracy in this patient population. Evolving research strives to better elucidate the pathogenic mechanisms of CTDs allowing for more targeted treatment modalities.

Cutaneous manifestations of lupus erythematosus: A practical clinicopathologic review for pathologists

Accurate diagnosis of connective tissue diseases is often challenging and relies on careful correlation between clinical and histopathologic features, direct immunofluorescence studies, and laboratory workup. Lupus erythematosus (LE) is a prototype of connective tissue disease with a variety of cutaneous and systemic manifestations. Microscopically, cutaneous LE is classically characterized by an interface dermatitis, although other histopathologic patterns also exist depending on the clinical presentation, location, and chronicity of the skin lesions. In this article, we review the clinical, serologic, histopathologic, and direct immunofluorescence findings in LE-specific and LE-nonspecific skin lesions, with an emphasis on lesser known variants, newly described features, and helpful ancillary studies. This review will guide general pathologists and dermatopathologists in accurately diagnosing and subclassifying cutaneous LE.

Immune Cell-Stromal Circuitry in Lupus Photosensitivity

Photosensitivity is a sensitivity to UV radiation (UVR) commonly found in systemic lupus erythematosus (SLE) patients who have cutaneous disease. Upon even ambient UVR exposure, patients can develop inflammatory skin lesions that can reduce the quality of life. Additionally, UVR-exposed skin lesions can be associated with systemic disease flares marked by rising autoantibody titers and worsening kidney disease. Why SLE patients are photosensitive and how skin sensitivity leads to systemic disease flares are not well understood, and treatment options are limited. In recent years, the importance of immune cell-stromal interactions in tissue function and maintenance is being increasingly recognized. In this review, we discuss SLE as an anatomic circuit and review recent findings in the pathogenesis of photosensitivity with a focus on immune cell-stromal circuitry in tissue health and disease.

Dermatologic Manifestations, Histologic Features and Disease Progression among Cutaneous Lupus Erythematosus Subtypes: A Prospective Observational Study in Asians

Introduction

Cutaneous manifestations are central to the primary diagnosis of systemic lupus erythematosus (SLE). However, information on the clinical, histopathologic, and direct immunofluorescence (DIF) features among subtypes of cutaneous lupus erythematosus (CLE), as well as longitudinal prospective observational study to evaluate the natural history and the progression to SLE, is lacking among Asians. Our objectives are to summarize the differences in the clinical, histopathologic, and DIF characteristics and serological profiles between various subtypes of CLE, and to provide its natural history and the association with disease activity in our Asian population.

Methods

A prospective observational study on CLE patients was performed between May 2016 and May 2020. Patients underwent full physical/dermatologic examination, skin biopsy for histology, and DIF. Systemic Lupus Erythematosus Disease Activity Index 2000 (SLEDAI-2K) scores and laboratory data were evaluated. Time schedule and characteristics for resolution and/or the disease progression to SLE were recorded in subsequent follow-ups.

Results

Of 101 biopsy-proven CLE patients, 25 had acute CLE (ACLE), 8 had subacute CLE (SCLE), 39 had chronic CLE (CCLE) only, 22 had CCLE with SLE, and 7 had LE-nonspecific cutaneous lesions only. Patients with exclusive CLE showed lower female preponderance, serological abnormalities, and correlation to systemic disease. However, when CLE was accompanied with any LE-nonspecific cutaneous manifestations, they were associated with high antinuclear antibody (ANA) titer, renal, hematologic, joint involvement, and greater SLEDAI score. Of 207 biopsy sections, SCLE/CCLE regardless of systemic involvement showed significantly higher percentage of superficial/deep perivascular and perieccrine infiltration than ACLE. On DIF, deposition of multiple immunoreactants was associated with higher systemic disease. Approximately 10% of CLE-only patients later developed SLE but had mild systemic involvement.

Conclusion

Our findings support that each CLE subtype has a diverse and unique character. Comprehensive understanding of the differences among CLE subtypes is important for achieving the correct diagnosis and providing appropriate disease monitoring and management.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13555-020-00471-y.

Skin Biopsy in Chronic Urticaria: When and Where and What to Look for?

Chronic urticaria is a relatively common condition in dermatology and is usually diagnosed on clinical grounds. Skin biopsy, however, may be indicated in certain cases to confirm diagnosis and rule out other conditions that can cause hive-like rashes. We review histopathologic findings seen in both chronic urticaria and other entities in the differential diagnosis. We then propose an algorithm of indications for skin biopsy in patients with hive-like rashes and suggest possible diagnoses based on the histopathologic findings.

Expert Perspective: An Evidence-Based Approach to Refractory Cutaneous Lupus Erythematosus

Cutaneous lupus erythematosus (CLE) is a chronic autoimmune disease that can present with a variety of skin manifestations and have a dramatic effect on a patient's quality of life. Effective treatment options for this disease are limited, and the efficacy of these treatments is often supported by low levels of evidence. This makes the treatment of refractory disease especially challenging, as it is difficult to achieve a consensus on the appropriate progression of treatment beyond first- and second-line treatment options. The treatment of refractory CLE often involves some degree of immunosuppression, which carries some risk for patients and requires a thoughtful approach to the selection of medications. Some treatments that have proven to be effective in systemic disease may not be as effective in cutaneous disease, making it difficult to extrapolate from the available evidence on systemic lupus erythematosus (SLE). Ultimately, the increased use of objective skin measurements in SLE clinical trials is necessary to understand drug efficacy in CLE and develop new treatments for this challenging disease. Here, we provide clinical examples of the challenges involved in treating refractory CLE, examine the evidence currently available for treatment options, and provide an algorithmic approach to the treatment of refractory disease based on this evidence. Novel therapies under development for CLE are also discussed, as they may soon be part of the accepted treatment regimen for refractory CLE.

An Update on the Pathogenesis of Cutaneous Lupus Erythematosus and Its Role in Clinical Practice

PURPOSE OF REVIEW

Understanding the pathogenesis of cutaneous lupus erythematosus (CLE) is an important step in developing new medications and providing effective treatment to patients. This review focuses on novel research within CLE pathogenesis, as well as some of the medications being developed based on this knowledge.

RECENT FINDINGS

The subtle differences between systemic lupus erythematosus (SLE) and CLE pathogenesis are highlighted by differences in the circulating immune cells found in each disease, as well as the specific pathways activated by ultraviolet light. Plasmacytoid dendritic cells and the related type I interferon pathway are major components of CLE pathogenesis, and as such, therapies targeting components of this pathway have been successful in recent clinical trials. B cell-depleting therapies have shown success in SLE; however, their role in CLE is less clear. Understanding the differences between these manifestations of lupus allows for the development of therapies that are more effective in skin-specific disease. Discovering key pathways in CLE pathogenesis is critical for understanding the clinical features of the disease and ultimately developing new and effective therapies.

New insights into the progression from cutaneous lupus to systemic lupus erythematosus

INTRODUCTION

Between 5 and 25% of patients with cutaneous lupus erythematosus (CLE) can progress to systemic lupus erythematosus (SLE) during the course of the disease. There is no clear predictive guideline for the progression of CLE to SLE.

AREAS COVERED

Lupus erythematosus (LE), a chronic autoimmune disease, has a wide spectrum of manifestations. On one side of the spectrum is CLE, in which patients only display skin lesions. On the other side of the spectrum is SLE, which develops severe systemic involvement. CLE has even been considered as a separate entity from LE, while CLE is also proposed to be associated with SLE. In this review, the authors will describe the relationship between CLE and SLE; summarize the incidence, risk factors, systemic involvement, and management of patients who transition to SLE. The literature search was conducted mainly through PubMed from March to July 2020.

EXPERT OPINION

The identification of clinical characteristics and biomarkers in patients facing risk of developing SLE and monitoring the disease on a regular basis are essential to promptly manage and hopefully prevent transition to the systemic form.

Clinical evaluation of total and high-avidity anti-dsDNA antibody assays for the diagnosis of systemic lupus erythematosus

Background

This study evaluated the diagnostic performances of total and high-avidity (HA) anti-dsDNA enzyme immunoassays (EIA) in Chinese systemic lupus erythematosus (SLE) patients.

Methods

A total of 410 serum samples from 217 SLE patients, 54 patients with other systemic autoimmune diseases, and 139 healthy subjects were tested on total and HA anti-dsDNA EIA, as well as three commercial in vitro diagnostic kits: BioPlex 2200 ANA Screen, Kallestad anti-dsDNA EIA, and Crithidia Lucilae IFA. The disease activities of SLE patients were assessed using the modified SLE Disease Activity Index. The diagnostic performances of each assay were analyzed using Analyse-it software.

Results

The diagnostic performances of the total and HA anti-dsDNA EIA kits were comparable to other commercially available in vitro diagnostic assays. Receiver operating characteristic curve analysis demonstrated an area under the curve ranging from 0.85 to 0.89, with the total anti-dsDNA kit demonstrating the highest sensitivity and the HA kit showing higher specificity. An overall agreement of >90% was observed between the total and HA anti-dsDNA EIA kits and commercially available quantitative anti-dsDNA kits. The ratio of HA to total anti-dsDNA antibody was significantly higher among SLE patients with active disease status and/or kidney damage. All assays exhibited a significant correlation with disease activity and multiple clinical manifestations.

Conclusions

While the clinical performances of various anti-dsDNA assays showed adequate agreements, the BioPlex 2200 anti-dsDNA assay demonstrated the highest positive likelihood ratio and odds ratio. The HA anti-dsDNA EIA kit in association with the total anti-dsDNA kit provided superior performance in SLE diagnosis and monitoring disease activity.

Vesiculobullous diseases in relation to lupus erythematosus

Vesiculobullous lesions in lupus erythematosus (LE) are a rare cutaneous manifestation of cutaneous and/or systemic LE with variable presentation. While the minor forms of LE-associated vesiculobullous disease may cause disfigurement and discomfort, the severe forms can present with hyperacute reaction and life-threatening consequences. Specific LE and aspecific cutaneous LE are defined by the presence or absence of interface change on histopathology that can be applied to vesiculobullous diseases in relation to LE. However, the diagnosis of LE-associated vesiculobullous diseases remains difficult, due to the poorly defined nosology and the similarities in clinical and immunohistopathological features among them. Herein, we thoroughly review the topic of vesiculobullous skin disorders that can be encountered in LE patients and organize them into four groups: LE-specific and aspecific vesiculobullous diseases, LE-related autoimmune bullous diseases, and LE in association to non-autoimmune conditions. We sought to provide an updated overview highlighting the pathogenesis, clinical, histological, and immunopathological features, laboratory findings, and treatments and prognosis among vesiculobullous conditions in LE.

Heterogeneous lupus-specific lesions and treatment outcome, in a single patient, over a period of time

The report highlights the importance of strict clinico-histological correlations when skin biopsies are performed in diagnostic doubt in systemic lupus erythematosus. Furthermore, PUVA is never indicated in autoimmune conditions involving photosensitivity, due to high potential for internal and cutaneous aggravation of the disease, as the authors observed in this case.

Peculiar histopathological features in minor salivary gland in lupus erythematosus

Salivary glands (SGs) can be affected by lupus erythematosus (LE). Many authors debate whether this condition is a secondary manifestation of Sjögren syndrome (SS) or a glandular aspect of LE. The present study investigated the histopathological aspects of biopsied minor salivary glands from LE patients to analyze their peculiar features that lead to xerostomia. Twenty-three minor labial salivary gland (MLSG) cases were included in the study; the diagnosis of LE was rendered according to the American College of Rheumatology criteria. Twenty-three healthy MLSGs were used as a control, for comparison. Regarding lupus MLSG, the presence of hyalinization and thickening of ductal basement membrane, perivascular inflammatory infiltrate, epithelial spongiosis with no ductal lymphocytic aggression, vacuolar degeneration of the ductal cells and acinar serous metaplasia were statistically significant compared to the control group. In the LE group, there was a statistically significant correlation between acinar atrophy and acinar fibrosis; acinar atrophy and ductal ectasia; acinar fibrosis and ductal ectasia; ductal atrophy and ductal spongiosis with no lymphocytic focus, interstitial inflammatory infiltrate intensity and vasculitis as well as vascular thrombi and vasculitis. There were no morphological differences between the three subtypes of lupus analyzed. Minor salivary glands from patients diagnosed with LE present peculiar histopathological changes and may be a multisystemic presentation.

The Cutaneous Spectrum of Lupus Erythematosus

Systemic lupus erythematosus is a complex autoimmune disease with a wide spectrum of clinical and immunopathological features. Cutaneous and articular manifestations are the most common signs in patients with systemic lupus erythematosus. We here review the pathogenesis and the new classification of cutaneous lupus erythemathosus with a discussion of the significance of the various cutaneous signs. The lesions are classified according to the level of the cellular infiltrate and tissue damage in the epidermis, dermis, and/or subcutis. Furthermore, cutaneous lesions pointing to the presence of a thrombotic vasculopathy and those due to a distinct inflammatory, neutrophilic-mediated reaction pattern are highlighted. Particular attention will be given in describing the histology of skin manifestation. Treatment options for cutaneous lupus erythemathosus have increased with the introduction of new biological therapies. However, the majority of the patients still benefit from antimalarials, which remain the cornerstone of treatment. The evaluation and management of cutaneous lupus erythemathosus patients depend on the clinical findings and associated symptoms.

Fas ligand promotes an inducible TLR-dependent model of cutaneous lupus-like inflammation

Toll-like receptors TLR7 and TLR9 are both implicated in the activation of autoreactive B cells and other cell types associated with systemic lupus erythematosus (SLE) pathogenesis. However, Tlr9-/- autoimmune-prone strains paradoxically develop more severe disease. We have now leveraged the negative regulatory role of TLR9 to develop an inducible rapid-onset murine model of systemic autoimmunity that depends on T cell detection of a membrane-bound OVA fusion protein expressed by MHC class II+ cells, expression of TLR7, expression of the type I IFN receptor, and loss of expression of TLR9. These mice are distinguished by a high frequency of OVA-specific Tbet+, IFN-γ+, and FasL-expressing Th1 cells as well as autoantibody-producing B cells. Unexpectedly, contrary to what occurs in most models of SLE, they also developed skin lesions that are very similar to those of human cutaneous lupus erythematosus (CLE) as far as clinical appearance, histological changes, and gene expression. FasL was a key effector mechanism in the skin, as the transfer of FasL-deficient DO11gld T cells completely failed to elicit overt skin lesions. FasL was also upregulated in human CLE biopsies. Overall, our model provides a relevant system for exploring the pathophysiology of CLE as well as the negative regulatory role of TLR9.

Ten-year retrospective clinicohistological study of cutaneous lupus erythematosus in Korea

An understanding of the differences in clinical manifestations and laboratory abnormalities between subtypes of cutaneous lupus erythematosus (CLE) is still lacking. The purpose of this study was to analyze demographic, clinical and histological features of CLE according to three main presentation subsets: acute (ACLE), subacute (SCLE) and chronic (CCLE). A 10-year retrospective analysis was performed on data from patients who were diagnosed with CLE between March 2005 and September 2015 in a Korean tertiary referral dermatology clinic. We compared demographic data and clinical and histological findings between three different CLE groups. An overall sample of 220 patients with CLE consisted of 67 patients with ACLE, 25 patients with SCLE and 135 patients with CCLE. Patients with CCLE regardless of systemic lupus erythematosus (SLE) presence had lower prevalence of anemia, urinary abnormalities and elevated erythrocyte sedimentation rate. Furthermore, CCLE patients who only had skin lesions showed lower female predominance, lower extracutaneous manifestation, fewer laboratory and immunological abnormalities including low antinuclear antibody titers and the lowest positivity for C3, C4 and anti-dsDNA, anti-Ro, anti-Sm and anti-RNP antibodies, and more prominent perieccrine inflammation and dermal fibrosis in histological findings. Considering distinct cutaneous manifestations of LE, a comprehensive awareness of each CLE subtype is important for achieving a favorable prognosis through appropriate diagnosis and management. This study provides comparative clinical and histological profiles of patients with different CLE subtypes in Korea.

Spectrum of orocutaneous disease associations: Immune-mediated conditions

There are a number of diseases that manifest both on the skin and the oral mucosa, and therefore the importance for dermatologists in clinical practice to be aware of these associations is paramount. In the following continuing medical education series, we outline orocutaneous disease associations with both immunologic and inflammatory etiologies.

Ultraviolet B Irradiation Causes Stimulator of Interferon Genes-Dependent Production of Protective Type I Interferon in Mouse Skin by Recruited Inflammatory Monocytes

OBJECTIVE

Photosensitivity is common in patients with systemic lupus erythematosus, although the mechanisms linking ultraviolet (UV) light to flares are not well understood. We undertook this study to determine whether repetitive UVB exposure could induce type I interferon (IFN) production in normal mouse skin, and to investigate the roles of inflammatory monocytes and plasmacytoid dendritic cells (PDCs) in type I IFN production and development of UVB irradiation-induced inflammation.

METHODS

Mice were irradiated with UVB at 100 mJ/cm² for 5 days, and cutaneous manifestations were examined by messenger RNA expression of inflammatory and type I IFN response genes, histology, and flow cytometry. Inflammatory monocyte and PDC depletion experiments were performed in CCR2-diphtheria toxin receptor (DTR)-transgenic mice and blood dendritic cell antigen 2-DTR-transgenic mice. The roles of type I IFN and of the adaptor protein stimulator of IFN genes (STING) in UVB irradiation-induced inflammation were investigated using IFN-α/β/ω receptor (IFNAR)-knockout mice and STING-knockout mice.

RESULTS

Repeated UVB irradiation stimulated an inflammatory cell infiltrate and induction of type I IFN and proinflammatory cytokines. Interestingly, the type I IFN response was independent of PDCs but dependent on inflammatory monocytes, which were recruited following UVB irradiation. The adaptor protein STING was necessary for both type I IFN and proinflammatory cytokine expression in the skin. UVB-irradiated IFNAR-knockout mice showed increased levels of proinflammatory genes and more severe inflammation by histology, suggesting a protective role for type I IFN.

CONCLUSION

In wild-type mice, repeated doses of UVB irradiation induce monocyte-dependent and PDC-independent expression of type I IFN together with expression of other proinflammatory cytokines. Induction is dependent on the adaptor protein STING. Surprisingly, studies using IFNAR-deficient mice revealed that type I IFN protects against UVB irradiation-induced skin inflammation, in part by attenuating proinflammatory cytokine expression and limiting tissue damage.

The Increased Expression of Toll-Like Receptor 4 in Renal and Skin Lesions in Lupus Erythematosus

Toll-like receptor 4 (TLR-4), a bacterial lipopolysaccharide sensor, is an innate immunity essential modulator. It is expressed on both immune and non-immune cells and may contribute to the cutaneous and renal manifestations during lupus erythematosus (LE). Our purpose is to evaluate TLR-4 expression and analyzing its role in lupus nephritis (LN) and chronic cutaneous lupus erythematosus (CLE) pathogenesis. TLR-4 immunohistochemical staining was performed on 30 LN renal biopsies compared with 11 healthy renal tissues and 30 skin biopsies from CLE patients compared with 15 normal individuals. CLE patients' biopsies showed a strong and diffuse TLR-4 expression throughout the epidermis and labeled inflammatory infiltrate and glands in the dermis whereas controls' skin expressed weakly TLR-4 only in the epidermis basal layer. LN glomeruli and tubules showed an increased and more intense TLR-4 expression compared with normal controls where TLR-4 expression was weak and rarely detected in glomeruli, diffuse and weak in tubules. A significant difference in TLR-4 expression between LN classes, both in glomeruli and tubules, was observed. These data confirm an up-regulation of TLR-4 expression in the affected tissues of CLE and LN patients and highlight the critical role of TLR-4 in the pathogenesis of cutaneous and renal disorders in LE.

Lichenoid and interface dermatoses

The terms 'lichenoid' and 'interface' dermatitis are often used interchangeably to describe an inflammatory pattern characterized histologically by damage to the basal keratinocytes in the epidermis. The mechanism of cell damage of such cells is now best understood as apoptosis, or programmed cell death. This inflammatory pattern of dermatoses, is also accompanied frequently by a band of lymphocytes and histiocytes in the superficial dermis, that often obscures the dermal-epidermal junction, hence the term 'lichenoid'. A discussion of the more common lichenoid/interface dermatitides encountered in the routine clinical practice encompasses the following entities: lichen planus, lupus erythematosus, dermatomyositis, erythema multiforme, graft versus host disease, fixed drug reactions, and multiple others.

Histopathologic Distinguishing Features Between Lupus and Lichenoid Keratosis on the Face

Background:

The occurrence of lichenoid keratosis (LK) on the face is not well characterized, and the histopathologic distinction between LK and lupus erythematosus (LE) occurring on the face is often indeterminate. The authors aimed to describe differences between LE and LK occurring on the face by hematoxylin and eosin alone.

Methods:

Cases of LK and LE were obtained using computer-driven queries. Clinical correlation was obtained for each lupus case. Other diagnoses were excluded for the LK cases. Hematoxylin and eosin–stained sections were reviewed.

Results:

Forty-five cases of LK and 30 cases of LE occurring on the face were identified. Shared features included follicular involvement, epidermal atrophy, pigment incontinence, paucity of eosinophils, and basket-weave orthokeratosis. Major differences between LK and LE, respectively, included perivascular inflammation (11%, 90%), high Civatte bodies (44%, 7%), solar elastosis (84%, 33%), a predominate pattern of cell-poor vacuolar interface dermatitis (7%, 73%), compact follicular plugging (11%, 50%), hemorrhage (22%, 70%), mucin (0%, 77%), hypergranulosis (44%, 17%), and edema (7%, 60%). A predominate pattern of band-like lichenoid interface was seen more commonly in LK as compared with LE (93% vs. 27%).

Conclusions:

The authors established the occurrence of LK on the face and identified features to help distinguish LK from LE. Follicular involvement, basket-weave orthokeratosis, pigment incontinence, paucity of eosinophils, and epidermal atrophy were not reliable distinguishing features. Perivascular inflammation, cell-poor vacuolar interface, compact follicular plugging, mucin, hemorrhage, and edema favored LE. High Civatte bodies, band-like lichenoid interface, and solar elastosis favored LK.

Approach to Cutaneous Lymphoid Infiltrates: When to Consider Lymphoma?

Cutaneous lymphoid infiltrates (CLIs) are common in routine dermatopathology. However, differentiating a reactive CLI from a malignant lymphocytic infiltrate is often a significant challenge since many inflammatory dermatoses can clinically and/or histopathologically mimic cutaneous lymphomas, coined pseudolymphomas. We conducted a literature review from 1966 to July 1, 2015, at PubMed.gov using the search terms: Cutaneous lymphoma, cutaneous pseudolymphoma, cutaneous lymphoid hyperplasia, simulants/mimics/imitators of cutaneous lymphomas, and cutaneous lymphoid infiltrates. The diagnostic approach to CLIs and the most common differential imitators of lymphoma is discussed herein based on six predominant morphologic and immunophenotypic, histopathologic patterns: (1) Superficial dermal T-cell infiltrates (2) superficial and deep dermal perivascular and/or nodular natural killer/T-cell infiltrates (3) pan-dermal diffuse T-cell infiltrates (4) panniculitic T-cell infiltrates (5) small cell predominant B-cell infiltrates, and (6) large-cell predominant B-cell infiltrates. Since no single histopathological feature is sufficient to discern between a benign and a malignant CLI, the overall balance of clinical, histopathological, immunophenotypic, and molecular features should be considered carefully to establish a diagnosis. Despite advances in ancillary studies such as immunohistochemistry and molecular clonality, these studies often display specificity and sensitivity limitations. Therefore, proper clinicopathological correlation still remains the gold standard for the precise diagnosis of CLIs.

Optical coherence tomography of cutaneous lupus erythematosus correlates with histopathology

Diagnosis of cutaneous forms of lupus erythematosus (LE), including chronic discoid LE (CDLE) and subacute cutaneous LE (SCLE), is usually based on characteristic clinical and histopathological findings. We aimed to visualize morphological changes in lesions of cutaneous LE using optical coherence tomography (OCT), and to correlate the OCT findings with histopathology. Six patients with CDLE and five patients with SCLE were investigated. Prior to skin biopsy, OCT assessment was performed on previously marked lesions. The images of OCT and corresponding histology were evaluated side-by-side on the PC screen. The thickening and disruption of the entrance signal in OCT images correlated with the hyperkeratosis which was observed in the histological sections. Atrophy of the epidermis, which was demonstrated by histology, could also be detected in the OCT pictures showing a thinned layer below the entrance signals. On OCT, a patchy reduction of reflectivity was observed in the upper dermis corresponding to dense patchy, partly lichenoid, lymphocytic infiltrates and oedema of the upper dermis. Furthermore, OCT images displayed increased signal-free cavities which histopathologically corresponded to dilated vessels in the upper dermis. All OCT parameters studied significantly (P < 0.05) correlated with histopathological features as indicated by coefficients of correlation ranging from 0.55 to 0.94. OCT enables to demonstrate micromorphological changes in cutaneous LE which correlate with histopathological findings. Nevertheless, the current technique does not allow one to visualize definite diagnostic features of cutaneous LE. However, OCT may be a promising method for objective monitoring of LE activity and treatment effects over time in vivo

Microarray study reveals a transforming growth factor-β-dependent mechanism of fibrosis in discoid lupus erythematosus

BACKGROUND

Discoid lupus erythematosus (DLE) is characterized by scarring lesions that develop and perpetuate fibrotic lesions. These are not observed in subacute cutaneous lupus erythematosus (SCLE). The pathophysiological basis of this is currently unknown.

OBJECTIVES

To identify contradistinctive signalling pathways and cellular signatures between the two type of lupus, with a focus on the molecular mechanisms leading to fibrosis.

METHODS

We conducted a gene expression microarray analysis in lesional and nonlesional skin biopsy specimens of patients with DLE (n = 10) and SCLE (n = 10). Confirmatory reverse-transcriptase quantitative polymerase chain reaction (RT-qPCR) and immunohistochemistry were performed on selected transcripts in a new cohort of paraffin-embedded skin biopsies (n = 20). Changes over time of a group of selected inflammatory and fibrotic genes were also evaluated in a second biopsy taken 12 weeks later. In vitro functional studies were performed in primary isolated fibroblasts.

RESULTS

Compared with nonlesional skin, DLE samples expressed a distinctive T-cell gene signature. DLE samples displayed a significant CD4 T-cell enrichment with an imbalance towards T helper 1 cytokine predominance and a relative increased forkhead box (FOX)P3 response. RT-qPCR and immunochemical analysis over time showed a progressive increment of fibrotic markers and persistent FOXP3 recruitment. Ex vivo upregulation of SERPINE1, MMP9, TGFBR1, phosphorylated SMAD3 and TGFB1 suggested a transforming growth factor (TGF)-β-dependent mechanism of fibrosis in DLE, also confirmed by the results observed following in vitro stimulation with TGF-β.

CONCLUSIONS

These results highlight major pathogenic pathways in DLE and provide novel molecular targets for the development of new therapies. The data suggest the existence of a TGF-β-dependent pathway inducing fibrosis in DLE.

Update on the role of plasmacytoid dendritic cells in inflammatory/autoimmune skin diseases

Plasmacytoid dendritic cells (pDCs) represent a specialized dendritic cell population that exhibit plasma cell morphology, express CD4, CD123, blood-derived dendritic cell antigen-2 (BDCA-2) and Toll-like receptor (TLR)7 and TLR9 within endosomal compartments. When activated, pDCs are capable of producing large quantities of type I IFNs (mainly IFN-α/β), which provide antiviral resistance and link the innate and adaptive immunity. While generally lacking from normal skin, pDCs infiltrate the skin and appear to be involved in the pathogenesis of several inflammatory, infectious (especially viral) and neoplastic entities. In recent years, pDC role in inflammatory/autoimmune skin conditions has been extensively studied. Unlike type I IFN-mediated protective immunity that pDCs provide at the level of the skin by regulated sensing of microbial or self-nucleic acids upon skin damage, excessive sensing may elicit IFN-driven inflammatory/autoimmune diseases. In this review, focus will be on the role of pDCs in cutaneous inflammatory/autoimmune dermatoses.

Rowell's syndrome in an Indian male and review of the literature

Lupus erythematosus (LE) with erythema multiforme-like lesions with its characteristic serological picture had been described in 1963. We report a 33-year-old married male who presented with skin lesions of various morphology on different body parts since four months. The skin lesions ranged from lupus-specific tumid LE to Rowell's syndrome and discoid LE. Histopathology of skin biopsy from all representative sites showed different forms of lupus erythematosus. Antinuclear and anti-double-stranded DNA was positive; however, serology for anti-SSA and anti-SSB was negative. There were no symptoms specific for organ involvement. It is unusual to document various morphological types in a single patient of lupus erythematosus. We document this case as all forms of cutaneous LE including Rowell's syndrome were evident in a single male patient.

Kutaner Lupus erythematodes

The diagnosis of cutaneous lupus erythematosus (CLE) requires a specific diagnostic approach to identify subtypes, to address differential diagnostic considerations, and to rule out systemic organ involvement. In addition to a detailed patient's history and clinical evaluation of the skin, histopathologic and immunofluorescent examination of a skin biopsy as well as laboratory screening are recommended. Photoprovocation tests can be performed to confirm the diagnosis of CLE and to assess photosensitivity in these patients. Recently, a scoring system for the activity of the cutaneous manifestations in CLE has been developed and validated which involves anatomical areas and morphologic signs of the skin lesions. In all subtypes of CLE, antimalarials are still the treatment of choice. Advances in biotechnology have led to the development of several novel agents for the treatment of autoimmune diseases; however, controlled trials have not been performed in patients with CLE. Furthermore, there is need for specific immunointervention, especially for patients who fail to respond to standard therapies. The second part of this review will enable the reader to differentiate CLE from other diseases and to suggest specific diagnostic procedures and treatment approaches.

Monoclonal antibody against macrophage colony-stimulating factor suppresses circulating monocytes and tissue macrophage function but does not alter cell infiltration/activation in cutaneous lesions or clinical outcomes in patients with cutaneous lupus erythematosus

This study's objective was to assess the effects of PD-0360324, a fully human immunoglobulin G2 monoclonal antibody against macrophage colony-stimulating factor in cutaneous lupus erythematosus (CLE). Patients with active subacute CLE or discoid lupus erythematosus were randomized to receive 100 or 150 mg PD-0360324 or placebo via intravenous infusion every 2 weeks for 3 months. Blood and urine samples were obtained pre- and post-treatment to analyse pharmacokinetics and pharmacodynamic changes in CD14(+) CD16(+) monocytes, urinary N-terminal telopeptide (uNTX), alanine/aspartate aminotransferases (ALT/AST) and creatine kinase (CK); tissue biopsy samples were taken to evaluate macrophage populations and T cells using immunohistochemistry. Clinical efficacy assessments included the Cutaneous Lupus Erythematosus Disease Area and Severity Index (CLASI). Among 28 randomized/analysed patients, peak/trough plasma concentrations increased in a greater-than-dose-proportional manner with dose increases from 100 to 150 mg. Statistically significant differences were observed between active treatment and placebo groups in changes from baseline in CD14(+) CD16(+) cells, uNTX, ALT, AST and CK levels at most time-points. The numbers, density and activation states of tissue macrophages and T cells did not change from baseline to treatment end. No between-group differences were seen in CLASI. Patients receiving PD-0360324 reported significantly more adverse events than those receiving placebo, but no serious adverse events. In patients with CLE, 100 and 150 mg PD-0360324 every 2 weeks for 3 months suppressed a subset of circulating monocytes and altered activity of some tissue macrophages without affecting cell populations in CLE skin lesions or improving clinical end-points.